Section 2.1.2 of AN4938 states:
If a USB interface is used (USB OTG_HS/OTG_FS), the associated GPIOs
powered by VDD33USB operate between VDD33USB_MIN and VDD33USB_MAX(see
Figure 2).
VDD33USB supplies both USB OTG_HS and USB OTG_FS transceivers. If only
one USB transceiver is used in the application, the GPIOs associated to the other
USB transceiver are still supplied by VDD33USB.
VDD = 1.8V, VDD33USB = 3.3V, using OTG2_FS, pins for OTG1_HS/OTG1_FS are assigned to various other peripherals.
Is this note saying that some GPIO configured as outputs will output 3.3V instead of 1.8V? If so, which pins? Those labeled "FT_u" and "TT_u" in the datasheet? This happens even if the pin is assigned to another peripheral, like SPI? If USB is disabled, it appears the output will be VDD. If the USB transition from disabled to enabled, does the output change from 1.8V to 3.3V?
Thank you
EDIT: My confusion is probably about what it means to be an "associated GPIO". Is any pin with a "_u" designation always associated? Or is it only associated when it is explicitly assigned to a USB peripheral?
